At present, in a wireless network based on orthogonal frequency division multiplexing (OFDM), load information is transmitted by using OFDM symbols. For example, in the 802.11a protocol standard, 12 OFDM symbols sent in the beginning are used as a preamble signal, and OFDM symbols following the 12 OFDM symbols are used to transmit load information. The load information is generally a data part of a physical layer, and may include a protocol unit, a data unit, and the like at a media access control (MAC) layer and an upper layer.
However, according to such a method in which load information is transmitted by using OFDM symbols, only the load information can be transmitted by using the OFDM symbols, and other information except the load information cannot be transmitted at the same time when the load information is being transmitted. Consequently, information transmission efficiency and transmission resource utilization are low.